Analysis of spices & herbs and its phenolic content by means of an electronic tongue

The drying process to which herbs and spices are submitted has a significant impact on the flavour and quality of those as many compounds might be degraded or transformed. This is especially relevant for most aromatic and bioactive compounds (e.g., phenolic compounds), which values have been reported to diminish during the drying process. In this direction, herein we explore the usage of an electronic tongue (ET) as a tool to assist on the monitoring of herbs and spices quality. The proposed approach is based on the use of a simple extraction method prior to the analysis of the samples with an array of voltammetric sensors in combination with pattern-recognition methods. Firstly, a partial least squares regression (PLS) model was built, which allowed the quantification of the total phenolic content (R2 > 0.985), an important indicator of their preservation. Subsequently, principal component analysis (PCA) of the obtained responses allowed also to qualitatively discriminate the different herbs and spices.